The present application relates to an electrolytic solution material used for an electrolytic solution of a secondary battery, and to an electrolytic solution and a secondary battery that use the electrolytic solution material.
In recent years, various electronic apparatuses such as a mobile phone and a personal digital assistant (PDA) have been widely used, and it has been demanded to further reduce the size and the weight of the electronic apparatuses and to achieve their long lives. Accordingly, as an electric power source for the electronic apparatuses, a battery, in particular, a small and light-weight secondary battery capable of providing high energy density has been developed.
In these days, it has been considered to apply such a secondary battery not only to the foregoing electronic apparatuses but also to various applications. Examples of such various applications may include a battery pack attachably and detachably mounted on the electronic apparatuses or the like, an electric vehicle such as an electric automobile, an electric power storage system such as a home electric power server, and an electric power tool such as an electric drill.
Secondary batteries utilizing various charge and discharge principles to obtain a battery capacity have been proposed. In particular, a secondary battery that obtains a battery capacity by utilizing insertion and extraction of an electrode reactant or precipitation and dissolution of an electrode reactant has attracted attention, since such a secondary battery provides higher energy density than a lead battery, a nickel-cadmium battery, etc.
The secondary battery includes a cathode, an anode, and an electrolytic solution. The electrolytic solution contains a solvent and an electrolyte salt. Since the composition of the electrolytic solution serving as a medium of a charge-discharge reaction largely affects performance of the secondary battery, various considerations have been made on the composition of the electrolytic solution.
Specifically, considerations have been made on various materials as additives of the electrolytic solution. In order to obtain a long life and a high capacity retention ratio, 4-methylene-1,3-dioxolane-2-one or the like has been used (for example, see Japanese Unexamined Patent Application Publication (Translation of PCT application) No. 2010-533359). In order to suppress degradation of battery characteristics under high-temperature environment, a phenol-based antioxidant or the like has been used together with halogenated ester carbonate (for example, see Japanese Unexamined Patent Application Publication No. 2011-154987). In order to improve high-temperature conservation characteristics, an antioxidant such as phenols has been used together with vinylene carbonate (for example, see Japanese Unexamined Patent Application Publication No. 2001-283906).